The present invention relates generally to container ends having non-detachable opening means for removal of the contents and more particularly to an improved tab arrangement for severing the score line as well as an improved method of attaching the tab to the end panel.
Because of the recent emphasis on ecology, the container industry has for years attempted to develop non-detachable substitutes for the familiar "pop-top" type of easy opening end in which the opening structure is completely separated from the container during opening.
The patented prior art is replete with numerous substitutes for the present generally conventional pop-top end such as "button" designs wherein a weakened area defined in the end panel of the container and a major portion if not all of the button is severed from the end panel to expose the contents. This type of opening means has not been generally accepted in the industry and the primary reason is believed to result from the fact that during the opening process, the force must be applied directly to the "button" which may cause the user to cut his finger on the sharp edge that is developed by severing the weakened line. Thus, this proposed alternate for the "pop-top" end has not been accepted commercially to any significant extent. Examples of the "button" design are disclosed in U.S. Pat. Nos. 3,227,304; 3,902,627; and 3,938,455.
Another proposed substitute for the present day conventional ends consists of a removable portion that is designed into the end of the container and a tab attached to the container outside the removable section with a nose portion of the tab overlying the removable section so that pivotal movement of the tab will sever the score line. Examples of this type of ecology end are shown in U.S. Pat. Nos. 4,024,981; 3,977,561; and 3,967,752. While this type of end has received some commercial acceptance, the acceptance has been severely limited because of the problems encountered in opening the end. Since the tab structure is offset a substantial distance from the center of the removable section, difficulties have been encountered in completely severing the scored line and moving the removable section a sufficient distance away from the opening created in the end panel to be unobstructed for removal of the contents.
Quite recently a further proposal has been made as a substitute for the "pop-top" end which is disclosed in U.S. Pat. No. 3,807,597. The end disclosed in this patent again was not accepted commercially because difficulties were encountered in completely severing the score line that ultimately produces the opening in the end panel.
Another type of substitute for the familiar "pop-top" can is disclosed in U.S. Pat. Nos. 3,924,777 and 3,949,898. Both of these patents disclose the formation of a well or recess produced in the end panel with a score formed in the base of the well and a special fitment is received in the well and has a lower edge that severs the score and is retained in the recess. However, this type of opener has not been accepted and it is believed that the reason is the special tooling that would be required to make the end.
Thus, while there have been literally dozens of proposed substitutes for the familiar completely severable tear strip with the attached tab, none of the proposed substitutes has received any degree of commercial success because they are either too complicated to operate, too expensive to produce or are unsanitary during use.